Heat exchange apparatus



Nov. 28, I939. K.-P. GROAT 2,181,230

- HEAT EXCHANGE APPARATUS Filed Nov. 5, 1937 2 sneet s sheet 1 attorneysHEAT EXCHANGE APPARATUS Filed Nov. 5, 19:57 2 Sheets-Sheet 2 AW, ////QPatented Nov. 28,1939

UNITED STATES I PATENT OFFICE i f nna'r sxcmnca APPARATUS Keith r.Groat, Canton, hio, assignor to York Ice Machinery Corporation, York,Pa, a corporation of Delaware Application November 5, 1937, Serial No.173,030

7 Claims.

and in certain types of plate one or more ports may be within themarginal Joint and another port or ports may be outside the marginalJoint.

The present invention permits satisfactory seals to be producedirrespective of the location of 'the through port with reference to themarginal joint.

For many years the advantage of forming the plates of thin sheet.metalpressed to produce flow controlling ribs or bosses has been recognized.The present invention is particularly adapted for use with plates ofthis type, but is capable of use with other types. In recent years,commercial heat exchangers have been constructed, making use of pressedplates formed of non-corrosive alloy steels, and the advantage of suchsteels, particularly in dairy apparatus, is too well known to requireelaboration. For. example, the patent to Seligman, 1,992,097, February19, 1935, shows a. plate of this general char- 'acter having fiatmarginal portions in which the through ports are formed and with whichthe necessary seals are produced by gasket carrying spacers interposedbetween successive plates. These spacers, as shown in the Seligmanpatent, comprise a frame which is grooved on opposite faces to receiverubber gaskets, the gaskets being cemented or vulcanized in place inthese grooves. 40 The only disadvantage of this construction is thepossibility that if the gaskets do not com- 'pletely fill the grooves,or if the gaskets are not closely cemented or vulcanized in place, smallfissures in which bacteria may breed are af- 15 forded. Even if thegasket carrier isinitially perfect, it may, after long use developfissures between the carrier and gasket.

Another patent to Seligman No. 2,075,236, March 30, 1937, eliminates thegasket carriers as separate elements and provides grooves formed atleast in part by pressing the plate, in which grooves the gaskets arecemented or vulcanized. This construction, while simpler than that shownin the earlier Seligman patent, is open to the same possibleobjection. 3

The present invention resembles the structure of the earlier Seligmanpatent to the extent that a separate carrier element is used, but itdifiers from that Seligman patentlin that the carrier is a thin plateand in that the gasket is 5 not mounted in a face groove but, on thecontrary, it is U-shaped in cross section and embraces the edge of asuitable opening formed in the carrier plate in such a way that theedges of the slot between the arms of the U-section of lo the gasket arepresented to the exterior of the heat exchanger, and consequently evenif a fissure between gasket and carrier plate be present, initially orafter use, it is wholly external to the 'path of fluid undergoingtreatment, and hence 15 harmless.

Another distinction-from the earlier Seligman patent above mentioned isthat the marginal portions of the plate, instead of being fiat, areofiset in such a way as to oiier a shoulder or abutment 20 against whichthe inner margin of the gasket ring seats. Consequently, when the platesare forced together and the gasket rings, which are customarily made ofrubber or the like, are compressed, their lateral expansion is resistedand limited by the shoulder on the plate. Since the shoulder limitsinward displacement, and the gasket carrier plate resists outwarddisplacement, undue distortion or spreading of the gasket is prevented.Hence the gasket is no moreseverely 30 deformed than it would be ifconfined in a groove. Another important fact is that the area of thegasket exposed to fluid pressure is small so that the total forcetending to glow the gasket out .is comparatively small. It follows fromthe facts 35 above set forth that the joint is sanitary and the gasketis adequately sustained against pressure and is forced to perform insuch a way that {the formation of internal fissures, even of a temporarycharacter, is minimized if not entirely 4o eliminated.

It may be asked why it is necessary in the structure of the two Seligmanpatents to cement or vulcanize the gaskets in place. The reason is thatthe-plates are customarily usedin the ver- 5 V tical position and arenot removed from the press for cleaning butv "are cleaned in suchvertical position. 4 Some means must be provided for holding therelatively flexible gaskets in place. Further, with thet'emperaturescustomarily used, 50 the gaskets if made of rubber,- as is the presentpractice in such heat exchangers, would have a tendency ultimately tolose thein precise form and dimensions unless'theywere adequately sus-The invention will now be described with reference to typical platesused in heat exchangers of this type. Where heating and cooling arecarried out in a single exchanger, and particularly where there isregenerative heating and cooling as is common in this art, the platesfor a single interchanger .assume various forms. There are commonly endplates, right hand plates, left hand plates, etc., which difier fromeach other chiefly in the location of the ports or in the presence orabsence of certain ports. These facts are well understood. Generallystated, the gasket plates conform to the heat transfer plates with whichthey are intended to be used.

For present purposes it is deemed sufficient to illustrate typical heatexchange plates and typical gasket plates for use therewith. Except asto cooperation with the gasket, the particular form of plate isimmaterial. Consequently, it should be understood clearly that no-eflortis here made to illustrate every possible form of gasket plate whichmight be used with the various known forms of heat exchange plate. Theillustration and description here given are to be considered exemplaryand not limiting. Gasket plates embodying the invention can be designedto meet every requirement of this type of exchanger by simply conformingthe gasket plate to the heat exchange plate -with which it is intendedto be used, according to principles illustrated by the examples chosenfor explanation.

In the drawings-- Fig. 1 is a face view of what is called a left handheat transfer plate. In the present specification the face of the platewill be defined as the raised or embossed side and the recessed orintaglio side will be called the bac The face view of a right hand plateis merely a mirror view of Fig. 1, that is, the parts shown in Fig. 1 onthe left will be on the right in the right hand plate, and vice versa.

Fig. 2 is a view of a gasket plate capable of use with all types of lefthand plates shown in Fig. 1 and all types of right hand plates of thesame design. In Fig. 2 it is shown in position to overlie the left handplate of Fig. 1. For use with a right hand plate the gasket plate wouldbe turned front to back, so that the upper annular port gasket would beto the right, and the lower an nular port gasket would be to the leftinstead of in the positions shown in Fig. 2.

Fig. 3 is a perspective view of the left hand plate of Fig. 1, with thegasket plate of Fig. 2 in position. 'Only the lower ends of the twoplates are shown and the parts are broken away so as to show theconstruction and particularly to show how the gaskets on the gasketplate seat against the flange and theshoulder of the heat transferplate.

Fig. 4 is a face view of what is called an end plate. This plate isordinarily used as one terminal plate of a series and differs from the.left hand and right hand plates in the fact that the space in its .facedoes not'communicate with any port.

Fig. 5 is a face view of a gasket plate for use with end plates such asthat shown in Fig. 4. Fig. 5 is drawn on a slightly larger scale thanFig. 4.

Fig. 6 is a fragmentary sectional view through the margins of threeadjacent plates with two interposed gasket plates. The first and secondplates (counting downward) are shown separated so that the gasket is notunder compression. The second and third plates are shown positioned as 7they would be under compression, the purpose of the view being toindicate the position and configuration of the gasket when performingits sealing function.

Fig. 7 is a sectional view drawn on a somewhat larger scale than theother views, showing an end plate, a left hand plate, a right handplate, a left hand plate and a right hand plate, assembled in the orderstated from right to left, between two clamping heads and with thenecessary gasket plates. The gasket plates at the opposite ends of theseries are of the type shown in Fig. 5. The others are of the type shownin Fig. 2. The line of section is indicated at 1-1 on Fig. 5.

Fig. 8 is a fragmentary view similar to the lower portion of Fig. 6 butshowing a possible modification omitting the gasket shoulder on the heattransfer plates.

Figs. Q and 10 show modified gasket plate constructions.

Before attempting a detailed description, it might be helpful to pointout that with heat exchangers of the type shown in the Seligman patents,the assembled plates are so formed as to afford intervening spaces.Assuming for convenience in discussion, that the liquid to be treated ismilk, the space between the first and second plates would afford apassage for heat transfer.

between the third and fourth for heat transfer medium, and so on inalternation through the series; An elaboration of the idea involvingwhat is called regenerative heating and cooling would involve heattransfer between warm milk and cold milk flowing in alternate intervalsbetween plates. For example, when used in conjunction with apasteurizer, warm milk entering the exchanger from the pasteurizer mightexchange heat with cold milk flowing to the pasteurizerthrough theexchanger.

The flow ducts through which the milk and heat exchange fluid approachand leave the heat exchange spaces are formed by registering theopenings in the stack of plates. These must communicate with the properheatexchange spaces and this result is produced, as it is in theSeligman patents, by causing the gasket which encloses the heat'exchangespaces between any two successive plates, either to embrace or toexclude the flow passage, depending on whether there is or is not to becommunication between the heat exchange plate and that particularpassage.

Generally stated, there are usually four passages in each plate, 1. e.,an entrance passage in each plate for heat exchange liquid and an exitfor heat exchange liquid, an entrance passage for milk and an exitpassage for milk. Only two of these can communicate with any particularheat exchange space.

However, it should be remembered that according to the treatmentdesired, the milk may flow through several heat exchange passages inseries, or it may flow through said passages in parallel, and the sameis true of the heat exchange liquid. Consquently, referring to the lefthand plate, Fig. 1 (and the same is true of its sary to elaborate.

ments of circulation. There are four possible arrangements of threeports. There are also four possible arrangements in which there isonlyone port and six possible arrangements -oi. two ports. Thus, for aleft hand plate there aresixteen possible port arrangements. Similarlythere are sixteen port arrangements for a right hand plate. The samething is true of the end plate, but. for practical purposes only a fewof the possible port arrangements are used. It is not deemed neces- Inthe practical manufacture of the plates, as proposed in Figs. 1 to 7inclusive, the manufacturing process is to strike up the boss formingthe shoulder around the port and then to cut the ports within the marginof this boss where ports are desired. Whether the boss has a port in itor not, it requires a gasket, and the gasket sealsin exactly the sameway whether the boss is ported or not. Since the present inventionrelates chiefly to the gasket structure and its coordination with theplate, it is unnecessary to elaborate the port arrangement because thelocation of the gaskets is the same whether the boss is ported or blank.I

All the plates, whether of the heat exchange, the end, or the gaskettype, may, if desired, have similar external outlines, and are so shown.The

plates have at their upper ends a perforated ear H and at their lowerends a slotted ear l2, this being chosen as a convenient supporting andalining means. The perforationsin ears receive the plate supporting rodI3 (Fig. '1) and the slotted ears i2 straddle a lower alining rod (notshown) to keep the plates in alinement. This is a known construction.Others may be substltut ed.

' Filler Referring now to the left hand plate 20L, Fig. 1, the plate ispressed from a sheet of stainless steel of uniform thickness. and hasaflat marginal portion M which surrounds the entire plate, anda centralraised area l formed by embossing the central portion of the plate. Themargin of the area i5 takes the form of a shoulder or offset |8.- In thearea i5 are pressed flow directing means here shown as cross ribs orcorrugations i1 intended to ensure sinuous turbulent flow of liquidacross the plate. These cross ribs are illustrative merely as onepossible flow directing means. Other forms may be substituted, theinvention imposing no limitations in this respect. In the constructionshown, each wave or corrugation carries at'its crest two reverselyextending dimples I3 and I9, intended to engage reversely ar ngedsimilar dimples on alternating plates and bus sustain the middles of theplates against displacement by fluid pressure differentials.

The plate 22L is illustrated as having four through ports 2|, 22, 23,24. The ports 2| and 22 are surrounded by independent upwardly embossedrims 25 and 23, while the ports and 24 are surrounded by embossed rims27, 28, which are not independent but are related to or formcontinuations of shoulder I. As explained, one or more of the ports 2|24may be omitted, but regardless oi this the rims 25-28 are present.

Between ports 23 and 24 on the one hand and raised area I! on the otherhand are depressions 29, 3|, which serve to connect ports-'23, 2,4 withthe interplate space on the face side of the plate. pieces 32, 33 (seeFig. 3) are welded into the grooves on. the back of the plates, suchgrooves being incidental to the rearward embossing of depressions. Thegrooves must be filled to which it is subjected tends to give a flatcontinuous sealing area for that gasket which seals against the back ofthe plate. Spacing dimples 34, 35 are struck up in the depressions 29,3|. 3

The ports 2|, 22, 23 and 24 are not cut un possible to form plates 20Lwith no ports, or

after the plate is embossed. Thus it is easily with 1 port (fourcombinations) 2 ports (six combinations) 3 ports (four combinations), aswell as four ports as shown (total 16 ported left hand plates). Whilethe plate having four ports' is the one commonly used the otherarrangements are used in certain cases.

The right hand plates 20R (Fig. 7) are merely right toleft counterparts(mirror reversals) of the plate L, Fig. 1. Right and left plates alter-1 natc in a stack and the reversal of dimples l8, l9, ensures that theconv sides of the dimples in one plate oppose the cvex sides of the dim-Dles in both of its neigh (see Fig. 7). i

The end plates 4| 0! Fig. 4 are similar except the ports in the plateare differently arranged. There is a fiat marginal portion 44surrounding the entire plate, 'a'central raised area 45 surrounded byshoulder 46. There are ribs or corrugations 41 with-dimples 48 and 49reversely arranged with respect to the dimples I8 and IQ of the lefthand plate 201'... This last arrangement is chosen arbitrarily andmerely entails the result that a left hand plate should adjoin an endplate to secure engagement of the dimples. There are through ports5|,52, 53, 54, each surrounded by an independent embossed rim 55, 56,51, 58. As in the case-of the plates 20L, 20R, there may be fewer thanfour ports, but the embossed rims are present in any case to ccact withthe gaskets.

rs, to limit deflection A gasket plate for use in the face of left handplates- 20L and right hand plates20R (irrespective oi the number ofports in such plates) slotted on their outer peripheries at $4 toreceive the margins of the openings in plate 60, which they embrace andto which they are cemented or vulcanized. Consideration of Fig. 6 willindicate that the metal to rubber joint between the gasket and itsgasket plate is outside the flow path in all cases and that when thegasket is under pressure the gasket-is closely conflned, is exposed tofluid pressure on only a small area and is sustained in nearly alldircetions. The compression to close rather than open or produce cracks,and consequently,

the diiliculties inherent in gaskets mounted in face grooves areavoided; Another advantage is that, since the gasket even in itscompressed-state (see the lower two plates Fig. 6, also the sealsvisible in Fig. 7) is much thicker than the plate,

any leakage past any gasket will drain outside the machine and noleakage grooves such as have heretofore been cut in the exchange, platesare necessary. There is a drainage space between gaskets SI and 32 andalso between GI and 63 (Fig.2), between 68 and "to 14 (Fig. 5) all veryclearly shown in Fig. 7.

The end gasket plate 55 (Fig. 5) has a central opening embraced by maingasket 66 and four through ports embraced by gaskets 6'I,'58, 69, 10,each formed and mounted as already described.

A consideration of Figs. 4 and-5 will make it clear that end gasket.plates 65 will seat on the face of end plates 40 and will seal with theback of any plate, particularly left hand plates ML plates as shown inFigs. 2 and 5 can be used with flat marginal or unshouldered plates ofthe type (for example) shown in Figs. 3 and 4 of Seligman Patent1,992,097. .This possibility is illustrated in Fig, 8 where 80, 8|represent two successive stacked Seligman plates and 60a representsapplicant's gasket plate with gasket Sla. The gasket Bla is not so wellconfined, as in the preferred construction, and because of the greaterarea of the gasket exposed to internal fluid pressure, is subject to agreater risk of blowing out if high pressures are used, but the jointbetween the gasket and itsgasket plate is outside the flow path ofmaterial flowing through the heat exchanger so that this desirablefeature is present.

While rubber is mentioned as the material for the gaskets andnoncorrosive steel as the material and other chemical action, mechanicalstrength,

and workability are important characteristics. The gasket. plates beingoutside the flow paths may be made of any suitable material, butnoncorrosive steel is contemplated as desirable.

Material for the gasket plates should have the necessary mechanicalstrength; and surface resistance to corrosion or other chemical actionis desirable but not so important as in the case of heat transferplates. Because of the simple form, workability is less important thanin the case of the highly embossed gasket plates. Thus the gasket platematerial and the gasket material may be coordinated, in any commerciallydesirabe way, to offer suitably formed bead gaskets with an externalsustaining plate with which the gasket is more or less permanentlyconnected. The important thing is that the gasket shall offer a smoothunbroken surface in the area exposed to flow paths of fluid within theexchanger.

Fig, 9 shows a modified construction of gasket plate in which the plate6%- is completely enclosed in rubber. The gasket bead Slb is extended asa thin covering which surrounds the plate b as shown, that plate beingotherwise substantially as shown in Figs. '2, 3, 5, 6, 7 and 8. Fig. 10shows another construction of gasket plate which may be used at leastwhere temperatures are not too high. Here the gasket bead Bic and theplate 600 are integrally formed but' have different physicalcharacteristics. Assuming rubber-as the material, bead He is of softvulcanized rubber and plate 600 is hard vulcanized, i. e., is what issometimes called hard rubaromather or vulcanite. Such diflferentiationsare familiar to persons skilled in the rubber art.

An important distinction from the structure of Seligman No.1,992,097,'is that the same gasket seals with both plates between whichit is interleaved. This applies to the various alternative forms ofgasket herein suggested.

While several modifications have been suggested, others are possiblewithin the scope, of i this invention and the specific disclosuresherein made are intended to be illustrative and not limiting.

What is claimed is:

1. In heat exchange apparatus of the separable plate type, thecombination of a series of heat exchange plates arranged in spacedstacked relationto form interplate flow channels, at least some of saidplates having through ports, some of which ports are adapted tocommunicate with said interplate channels; gasket plates interleavedbetween the heat exchange plates and having an opening conforming tosaid interplate channels and said communicating ports, and at least oneport adapted to register with another port in the heat exchange plates;gaskets carried by said gasket plates and surrounding said opening andports, each such gasket sealing with the twoheat exchange plates betweenwhich the gasket plate is interleaved and the plates being formed withshoulders coforming to the internal contour of the gaske ,and serving tolimit inward displacement of the gaskets, under sealing pressure,whereby flow of the gaskets and the gasket area exposed to fluidpressure are minimized; and clamping means between which said plates areconfined under seal producing pressure. 7

2. A gasket plate for heat exchange apparatus of the plate type,comprising a plate having at least one opening therein; and a resilientgasket embracing and enclosing the wall of said opening and permanentlysecured thereto to present an unbroken surface within said opening andsealing surfaces at opposite faces of the plate, said opp sed sealingsurfaces being of small transverse dimension as compared with adjacentportions of the plate, which plate extends from an the plate extendingbeyond the gasket suihciently to serve as a rigid beam resisting outwarddisplacement of the gasket.

4. A sealing gasket plate for plate type heat exchangers, comprising ametal plate having at least one fluid flow opening therein; and a.continuous gasket channeled in cross section, and secured to the edge ofsaid opening in such manner that the'joint between the-gasket and themetal'is remote from said flow opening and an unbroken gasket surface ispresented thereto, the plate extending from the bottom-of the channel inthe gasket a substantial distance beyond the gasket, whereby a gasket ofmoderate sealing area is adequately sustained against outwarddisplacement by the plate.

5. A sealing gasket plate for interposition between the heat exchangeplates of plate type heat exchangers, and comprising a metal platehaving a polygonal fluid flow opening therein; and a channeled sealinggasket adapted to seal with the plates between which it is interposed,said gasket surrounding said opening with the marginal portion of saidopening in said channel and the joint between said channel and the edgeof the plate around the opening facing away from the consequentlyisolated from contact with fluid flowing through the said opening by theseals formed between the gasket and the adjacent heat exchange plates, aportion of the plate thinner than the gasket even when compressed,extending outward beyond the gasket and serving to sustain the gasketand resist its distortion while affording a 4 drainage path for leakage.

6. In a heat exchanger of the separable plate type, the combination of aseries of heat exchange plates arranged in spaced stacked relation toform interplate flow channels, at least some of said plates havingthrough ports some of which ports are adapted to communicate with saidinterplate channels, said plates being oflset to form continuousshoulders one of which surrounds an interplate flow channel and anotherof which surrounds a port in the plate; apertured gasket platesinterleaved between successive exchange plates, the apertures in saidgasket plates conforming to but being larger than the areas embraced bythe shoulders on the heat exchangeplates whereby the gasket plates arereceived between the ofiset portions of the heat exchange plates;continuous gaskets mounted on and enveloping the margins of theapertures in each of said gasket plates and sealing .with ofisetportions of the two adjacent heat exchange plates and with the shoulderon one of said plates, the gasket plates having suiiicient width outsidethe gaskets to sustain the gaskets against outward displacement and theshoulders on the heat exchange plates serving to sustain the gasketsagainst inward displacement and to limit the area of the gasketssubjected to fluid pressure; and clamping means between which saidplates are confined under seal producing pressure.

7. A gasket plate for heat exchangers of the separable plate typecomprising a substantially rigid plate having an opening therethrough,and a resilient gasket on the margin of said opening and permanentlyattached to said plate, said gasket presenting a continuous unbrokensurface within the opening and sealing areas projecting above both facesof said plate and each surrounding said opening, and the plate having aportion external to the gasket and adapted to serveas a stifieningmember which sustainsthe gasket against outward displacement.

KEITH P. GROAT.

} CERTIFICATE OF CORRECTION; Patent No- 2,181,2 0. r November 28, 19 9.

-ICEITH P. snow.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page.5,first column; line 12, claim 5, for the words "from the read from and;and that the said Letters Patent should be read with this correctiontherein that the same may conform to the record of the case in thePatent Office.

Signed and sealed this 26th day of December, A; D. 1959.-

I Henry Vai1 Arsdale, (Seal) 4 Acting Connniasioner of Patents.

